A. Field of the Invention
The present invention relates to a lock-up clutch mechanism, more particularly, to a lock-up clutch mechanism arranged within a torque converter for transmitting torque from a front cover of the torque converter to a transmission side of the torque converter.
B. Description of the Related Art
The torque converter is a device that has a torus, which includes three different runners, i.e., an impeller, a turbine and a stator, and transmits driving force via hydraulic fluid contained in the torus. The torque converter generally includes a lock-up clutch mechanism arranged in a space between the front cover and the torus.
The lock-up clutch mechanism is a device that allows for selective mechanical transmission of torque from the front cover to the transmission side of the torque converter and includes a clutch coupler and a damper mechanism. The clutch coupler includes a piston, which is freely moveable in an axial direction, and a friction member, which is provided on the piston. The clutch coupler engages with or disengages from the front cover in accordance with hydraulic pressure changes within the torque converter. The damper mechanism is composed of, for example, a plurality of torsion springs and is capable of absorbing or reducing torque fluctuation, which is transmitted from the clutch coupler, by the torsion springs.
The damper mechanism in the lock-up clutch mechanism is generally located at an outer peripheral region in order to reduce an axial size of the entire lock-up clutch mechanism.
However, there are also lock-up clutches that include a damper mechanism that is located radially inner peripheral regions thereof. In a case of a lock-up clutch mechanism in which the damper mechanism is arranged at the inner peripheral region of the turbine, the torsion springs constituting the damper mechanism are held between two disk-like plate elements acting as a torque input side member, and a torque output side member is arranged between these plate elements and engages with the torsion springs. A problem with such configurations is providing the two disk-like plates with appropriate portions that support the springs.